The invention relates to a cutting subassembly for machines. A panel-like workpiece is moved continuously in a rectilinear manner in order for edge-material overhangs projecting beyond the front and/or rear transverse sides of the workpiece, which are oriented substantially transversely to the movement direction of the workpiece, to be cut off by a cutting subassembly. The cutting subassembly is provided on the longitudinal sides of the workpiece, the longitudinal sides running parallel to the movement direction. The cutting subassembly has a saw unit which comprises a motor-driven saw blade and which is mounted such that it can be displaced between a position above the workpiece and a position beneath the workpiece. The cutting subassembly also has a contact element which is associated with the saw blade and at least one contact surface. With such a cutting subassembly it is possible for the contact surface to be engaged against the front or rear transverse side of the workpiece and for the cutting plane of the saw blade to be oriented in alignment with the contact surface.
Such cutting subassemblies are known from EP 0 538 513 B1. They are used, in particular, in the case of edge-banding machines for gluing edge material onto a longitudinal side of the workpiece. Following the gluing operation, the glue-on edge has an edge overhang which can be cut off by means of the cutting subassembly.
For the cutting-off operation, use is made of a saw unit with a saw blade which is usually driven by means of an electric motor. The saw unit can be displaced between a position above, and a position beneath, the workpiece, in order to cut off an edge overhang by the saw blade during the movement.
The contact element is used in order to orient the saw blade level with the front and/or rear transverse side of the workpiece, it being possible for the cutting plane of the saw blade to be oriented in alignment with the contact surface of the contact element.
If the cutting plane is oriented in alignment with the contact surface, then the edge overhang is cut off by a saw cut oriented perpendicularly to the movement direction of the workpiece. Such an orientation is usually selected when edge material is glued onto the longitudinal sides of the workpiece, but not onto the transverse sides of the workpiece. In many cases, however, edge material has already been provided on the transverse sides in a preceding operating step. If the longitudinal side of the workpiece is then also to be covered by edge material, it is necessary to ensure, for the operation of cutting off edge overhangs, that the saw blade does not damage the edge material which has already been glued onto the transverse side. For this purpose, the saw blade is oriented obliquely in relation to the contact surface, with the result that the saw blade assumes an angle of less than 90° in relation to the edge material glued onto the longitudinal side of the workpiece. Therefore, during the operation of cutting off an edge overhang in a flush manner, the edge material glued onto the transverse side is not damaged. Orienting the saw blade obliquely in relation to the contact surface, in the case of known cutting subassemblies, necessitates high-outlay conversion, which can only be carried out by skilled personnel. This conversion is associated with a considerable outlay in terms of time and costs.
DE 37 17 207 A1 discloses a cutting subassembly in which the saw blade, for cutting off the front and the rear edge overhangs, can be pivoted between two predetermined fixed positions, each position oriented obliquely in relation to the corresponding contact surface. The saw blade is mounted on a saw unit which is retained in a pivotable manner in guide slots. The guide slots define fixed oblique positions which the saw unit inevitably assumes when cutting off an edge overhang. Changing the oblique position is not envisaged, nor is orientation of the saw blade in alignment with the contact surface.
It is an object of the present invention to develop a cutting subassembly of the type mentioned in the introduction such that the orientation of the saw blade relative to the contact surface is simplified and can be changed in a straightforward manner.